Hydraulic pressure transformer



Dec. 25, 1951 HJARPE 2,579,670

HYDRAULIC PRESSURE TRANSFORMER Filed March 24, 1949 5 Sheets-Sheet l E?w a?" a hyww Dec. 25', 1951 E. G. HJARPE 2,579,670

HYDRAULIC PRESSURE TRANSFORMER Filed March 24. 1949 3 Sheets-Sheet 2Fig.5

Dec. 25, 1951 H A 2,579,670

HYDRAULIC PRESSURE TRANSFORMER Filed March 24. 1949 3 Sheets-Sheet 5Patented Dec. 25, 1951 HY DRAULIGPRES SURE TRANSFORMER -EricGeorg-Hjarpe, Goteborg, Sweden, assignorrto MAktiebolaget SwenskaKullager fabrikcn,JGoteborg,Sweden, a corporation of Sweden ApplicationMarch 24, 1949, SeriaFN 0183 wInlSweden April 2, 1948vl-Jnstance.rioraririving a mechanismnwhichfor'its Junction. requires ahigher liquidspressureithan Since "the, quantity ofapressure .ithat;available.

illiquid consumed iswas a rule very vairiablef itl isl,necessaryiijthatlthe quantity of liquid i'shall' be variablefromthemaximumdownto nil.

Certain "devices which have been proposed" for this purpose have. beenprovided with a "relief valvethrou gh which'the surplus .liquidinotusedfor driving purposesinay escape. IAsdi'sadvanof" heat whichiistransferred toithe liquid," the viscosity. of which is hereby usually"considerably altered.

In other systems a part of the 'availablefiuid'Iisus'ed'todrive1a:liquid motor; which is directly connected to ahigh'pressure pump. "lf themotor isof rotary type the ificiencrwill be'quite-low,

andthe effect Which-is lost:is'transformedto-heat,'

which in this case also"is-"-transferred* to "the liquid.

l Devices having"reciprocating pistons as hith-en to used" are-- rather"complicated and expensive;

ance-the pistonsare mutually mechanically interconnected; as is also thecasewith the governing Val-ves. Such devices also have certain otherdisadvantages such as uneven delivery, etc.

The device" according to the 1 present invention is governed preferably--en'tirely by hydraulic -meansby valves which arealso'hydraulically'governed. The -wholeaggregate will thus he simple andflexible and" there vill be h ai tlly any wear "on the parts.

' embodiment of "the-invention is showm on the accompanying drawingswhereiflFigss 1 to 5 a-r l'i-ke' fna'gmentary sectional vie-ws showingthe respective positions on the parts of the trans- "-iormer duringdifferent phases "of the cycle. The numeral I indicates the inletline-ior a-pressm'e 'liqixidj-From the inlet line the fluid' fiovvsthrough 'I'hese'valvesare opene dlay the pressure of the liquid,.,permitting the liquid 'to--'obtain=-access througlr channels ll" and42 to the minor cylinders 6 and I of a, pair ,of differential pistons,where it acts on the pistons 8-and 9 moveable win lthesei cylinders.

to assume their lower positions-Has long: as there are no other forcesacting-upon-them. The pressure liquid. is also led from the inlet 1 toa, valve chamber IQ and to another'valve chamber H a'pairof-piston-valves 5 2 and I3.

the" position is thatshown in l fig ilithe Pliquid is led from thevalvechamber I through a-channe1-*I4-to' a'valve chamber l5. iII'IZhe; valvefchamber 16' at the'other endyoffthe pistonvar'lve The :pistonsxare thuscaused I l3r-is in communication withanoutlet lhthron'gh eatchannel ll,atchamber 19min the valve 12. 'a channel: 35 an annulan channel36-i-whichsurroundssthevalve l3 and a channel 34. MInuthe position shown1311B, liquid-l. continues irorn lithe valve. chamber 1 l through-a1channel: 20. toathe Working cylinder v,2 I -ofoneoof the :difierentia-l-pistons,'- where, it exertsa pressure'on. the piston 22- which may;forexampleybe five timesasgreat in as the pressure exerted by the liquidon the apistont 9, if the-rareas =of the pistonsare1asll 5zl..erEquilihriumflwillt ltheref ore t not be. attained until until thegaleton unit 9-22 hasmoved sofast-that the specific, pressure tinwthercylinder 1 ihaswincreasedrto five times the specific pressureloft/theliquid entering through-the. inlet duct l 'I he' liquid t in thesmallerv cylinder I thus forced past. a ball valve 23 out winter a,ductlf24 I :leadingto a Working Hcylinderlonthelike.

w 'Ihc-,.. ball val-ves- 5.ancl -2 5 are kept closedlbyQthe higherliquid pressure. o Whenlthee biston unit 9422 ,hasnmovedw so far that(it ppensra channel a 26 leadingfinom. the cylinder 2 Into; a valve,chambenl'latostheright of :the valve L2, "the.-,liquidmis gasledrthroughthis channel .toilthe said valve cham- Ll her: and forces the valve .1 2towardsthe left. 'lTThis r movementfis.made possiblesince the valvechamcberwmratethe left endgof the valvemislinlcommunication with other.outlet 1 T ithrou'gh'. the ;channel :-3: l.29, the supper. partflliiflof thercylir'ider. andfthe Johanna-11 3 I. 'Th epposition'. is now thatshown in Fig.2.

The displacement of Ithe valve 1 i 2 U; puts the val ve.chambe1 l SIincommunicationtvvitli the inlet I. and pressure liquid hows" froin theinlet 'throu'glfthe channel l8 to the valve: chvaxnberil 6 and forcesthe valve 13 to the rightwhiclris ,Apos'sible. since (the valve-chamber15 incomrmimication witlfthe outleti'l'l through thehhan- 40 nel" 14,the valvecharnber Ill; a-channeltzleading. from the latter to an annularchannel33 which surrounds the valve13 and the channel" 34. The.displacement of the valve 'i3"('seeFig."3) puts' a valve chamber 3'!the-valve" I 3" in communi'cation' with the inlet IV and thecylinder 2|@is put in communication with "the outlet 'l I through .itherfchannel20, valve chamber l l,"=an annular channel 36 surroundingtthe valve 13and the 'ch'annerii l. The pressurefliquidnow flows from the channel 1through the? valve chamber I 9, channel"2,valve chamber 31"ancl' achannel 3 Bfito a workingcylinder 39',"Where "it exerts pressure .on apiston iflflwhi'ch' is connected to-the bistonl 3. The'pressure liquidthen forcesithe piston unitflflfiin a' direction towardsthemmlidBl"B'in" which the specific pressure increases LtO" five'times the pressureof "the liquid entering '5 through the inlet 1. Thei liqhidin the"cylinder G is forced outofthe cylinder;past'the'ballvalve 1 2 5.. and"out new the ,ductf 24f "leading" tothe; place that communication isopened between the cylinder 39 and the channel 29, liquid flows throughthis channel to the valve chamber 28 and forces the valve I2 towards theright back to its ori inal position, which is possible since-the valvechamber 2! at the other end of the valve by the previously mentioneddownward movement of the piston unit 9-22 has been put intocommunication with the outlet ll-thrcugh the channel 2%, a channel 43which connects the cylinder parts 30 and 44, the upper part 44 of thecylinder, the

channel 43, the cylinder part 39 and the channel3l.

By the displacement of the valve l2 towards the right (Fig. 4) the valvechamber ID has again been put into communication with the inlet i andthe liquid flows through the channel 14 to the valve chamber I5 anddisplaces the valve I3 back, to its original position, since the valvechamber [6 is again in communication with the outlet I! through thechannel N3, the valve chamber 19, the channel 35, the annular channel 36and the channel 34. The position of the valves is now that shown in"Fig. 5. The liquid now again flows from the inlet I through the valvechamber ID, the channel 2, the valve chamber II and channel to thecylinder 2| and displaces the piston unit 9--22 upwards so that thespecific 5 pressure increases in the cylinder 1 to the higher 'pressureand holds the ball valves 5 and ,closed, the liquid passing the ballvalve 23 into the duct 24. The pressure in the cylinder 6 will bethesame as that in the inlet I and forces the piston unit B-- in thedirection from the cylinder 6, since the cylinder 39 is again incommunication with the outlet I! through the channel 38, valve chamber31 and channel 34. The position of all parts is now once more that shownin Fig. 1.

The working cycle described above is contin- Tuously repeated as long asliquid is removed from the outlet duct 24. I'he speed of the pistonunits 9-22 and 6-40 is governed by the liquid consumption aslong as thecapacity of the apparatus is not exceeded.

In order to prevent momentary drops in pressure inv the duct 24 when thevalve I3 is reversed from one end position to the other the valvechamber H and 31 in the valve are never out ofi from the inlet at thesame time. In other words the cylinders 2| and 39 are never pressurelesssimultaneously. 7

. When the device is used for feeding machines with very considerablevariations in liquid consumption, for instance machines havingalternately a slower feed and swift reverse it is of advantage tointroduce a reversing valve between the device and the machine forautomatically connecting the machine to the high pressure line or thelow pressure line as required. For quick maneuvering when theconsumption is great but the pressure not high, the machine is thusautomatically connected directly to the low'prestionary. When themachine is running with ordinary feed during the working phase whenhigher pressure is required but the liquid consumption is much lower itis automatically connected to the high pressure line from the apparatus.

Having thus described my invention I claim and desire to secure thefollowing by Letters Patent:

1. A hydraulic pressure transformer having a. plurality of difierentialpistons, each reciprocating in a low pressure cylinder and a highpressure cylinder, means for putting the low pressure cylinders intointermittent communication with a primary duct for pressure liquid andmeans for intermittently putting the high pressure 'cylinders.alternately into communication with a low pressure duct such as the saidprimary duct and a high pressure duct, the movement of the saiddifferential pistons being controlled by automatically controlledgoverning means in such a way that liquid is always being delivered fromat least one of the high pressure cylinders, the movements of the saidgoverning means being hydraulically controlled by the movements of thesaid differential pistons.

2. Hydraulic pressure transformer according to claim 1, characterizedthereby that each high pressure cylinder is provided with a check valve,through which it is intermittently put into communication with a commonpressure line.

3. Hydraulic pressure transformer according to claim 1, characterized bya check valve between the low pressure duct and the high pressurecylinder of the differential piston.

4. Hydraulic pressure transformer according to claim 3 characterizedthereby that each high pressure cylinder is provided with a check valvethrough which the cylinder is intermittently put into communication witha common pressure line.

5. Hydraulic pressure transformer according to claim 1 characterizedby'piston valve means for distributing the fluid to the low pressurecylinders.

6. Hydraulic pressure transformer according to claim 1, characterizedthereby that the control means includes channels from the low pressurecylinders, the mouths of the channels being positioned so as to beuncovered to the piston actuating hydraulic pressure only when thepistons have reached predetermined positions in the pressure strokes.

7. Hydraulic pressure transformer accord n to claim 6 wherein the pistonvalve means is operatively connected by channels to the low pressurecylinders, the mouths of the channel being positioned so as to beuncovered to the piston actuating hydraulic pressure only when thepistons have reached predetermined positions in the pressure strokes.

ERIC GEORG HJARP REFERENCES CITED The following references are of recordin the file of this patent:

- UNITED STATES PATENTS Number Name Date 1,451,303 Mitchell Apr. 10,1923 1,600,384 Aikman Sept. 21, 1926 2,231307. Wallacef Feb. 11, 19412,279,364 Cadbury Apr. 14, 1942 2,293,076 Ponting Aug. 18, 19422,340,929 Cadbury Feb. 8, 1944

